1. Field of the Invention
The present invention relates to a vibration-damping structure for an audio apparatus.
2. Description of the Related Art
Conventional home theater systems have become widespread, in which a plurality of speakers are used to provide a realistic sound field in a household use, for example. For example, an audio apparatus called an “AV amplifier” is used in a home theater system for outputting audio signals to a plurality of speakers (see, for example, Patent Document 1 (Japanese Laid-Open Patent Publication No. 2006-129147)).
An audio apparatus such as an AV amplifier includes therein a signal processing board for processing audio signals and an amplifier circuit board for amplifying the audio signals. An AV amplifier is provided with a power transformer for stepping down the input power source voltage and an exhaust fan for discharging the air inside. Such an AV amplifier provided with a tuner is sometimes called an “AV receiver”.
FIG. 7 is a perspective view showing an example of a conventional AV amplifier. Note that FIG. 7 does not show a top cover for covering the top of the assembly. The “front” direction as used herein is the lower left direction in FIG. 7 and the “rear” direction is the upper right direction in the figure. The “right” side and the “left” side are the right side and the left side, respectively, of the AV amplifier as viewed from the “front” direction.
The AV amplifier includes an assembly 81 having a generally rectangular parallelepiped shape. The outer shape of the assembly 81 is generally defined by a lower chassis 82, a front panel 83, a rear panel 84, a pair of left and right side panels 85, and a top cover (not shown). The lower chassis 82 includes a bottom plate member 86 being a flat plate, and a pair of side plate members 87 extending from the left and right end portions of the bottom plate member 86 in a direction perpendicular to the bottom plate member 86.
Provided inside the assembly 81 are a signal processing board 88 and an amplifier circuit board 89 on which electronic components such as capacitors and chip resistors are mounted. Also provided inside the assembly 81 are a power transformer (toroidal transformer) 90, an exhaust fan 91, a heat sink 92, etc. More specifically, components such as the signal processing board 88, the amplifier circuit board 89, the power transformer 90, the exhaust fan 91 and the heat sink 92 are directly fixed on the upper surface of the bottom plate member 86 of the lower chassis 82 described above.
In a home theater system using the AV amplifier, a DVD player (not shown), a television set (not shown) and a plurality of speakers (not shown) are connected to the AV amplifier, for example. When the AV amplifier receives a video signal and an audio signal from the DVD player, the AV amplifier processes (decodes) the audio signal from the DVD player and outputs the processed signal to the speakers, while processing the video signal from the DVD player and outputting the processed signal to the television set.
In this conventional AV amplifier, the power transformer 90 and other components are directly fixed on the upper surface of the lower chassis 82, as described above. When the AV amplifier is powered ON, the power transformer 90 and the exhaust fan 91 start vibrating, and the vibrations are transmitted to the lower chassis 82. Then, the vibrations are transmitted also to the signal processing board 88 and the amplifier circuit board 89, which are fixed on the upper surface of the lower chassis 82. Vibrations of the power transformer 90, etc., influence the audio signal being processed by the signal processing board 88 and the amplifier circuit board 89. Specifically, the audio signal is contaminated with vibration-induced noise, which affects the quality of the sound output from the speakers.
In view of the above, an object of the present invention is to provide a vibration-damping structure for an audio apparatus, capable of damping the vibrations of the power transformer and the exhaust fan to thereby suppress the influence of the vibrations on the audio signal.